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Many animals regularly visit mineral licks to consume clay, supplementing their diet with nutrients and minerals. Some animals require the minerals at these sites not for nutrition, but to ward off the effects of secondary compounds that are included in the arsenal of plant defences against herbivory.[2] The mineral contents of these sites usually contain calcium (Ca), magnesium (Mg), sulfur (S) phosphorus (P), potassium (K), and sodium (Na).[3][4][5][6] Mineral lick sites play a critical role in the ecology and diversity of organisms that visit these sites, but little is still understood about the dietary benefits. "The adjectives ‘mineral’ and ‘salt’ bear witness to the common proposition, in the ecological literature, that animals eat soil to satisfy a craving for nutrient minerals, resulting from inadequate forage. However, for wild animals which frequent licks, sodium is the only mineral identified so far, with strong evidence that an extra supply is indeed needed and sought in some cases."[7]:107

Nonetheless, many studies have identified other uses and nutritional benefits from other micronutrients that exist at these sites, including selenium (Se), cobalt (Co) and/or molybdenum (Mo).[8][9] In addition to the utilization of mineral licks, many animals suffer from traffic collisions as they gather to lick salts accumulated on road surfaces. Animals also consume dirt (geophagy) to obtain minerals, such as moose from Canada mining for minerals from the root wads of fallen trees.[10][11]

People use salt licks in the husbandry of livestock and to attract or maintain wildlife, whether it be for viewing, photography, farming, or hunting purposes. Maintaining artificial salt licks as a form of baiting is illegal in some states in the United States, but legal in others.[6]:413

In Norse mythology, before the creation of the world, it was the divine cow Audhumla who, through her licking of the cosmic salt ice, gave form to Buri, ancestor of the gods and grandfather of Odin. On the first day as Audhumla licked, Buri's hair appeared from the ice, on the second day his head and on the third his body.[13]